Washington, Dec. 27: Federal officials said Umar Farouk Abdulmutallab has told them he had obtained explosive chemicals and a syringe that were sewn into his underwear from a bomb expert in Yemen associated with al Qaida.

The authorities have not independently corroborated the Yemen connection claimed by the Nigerian youth who tried to trigger an explosion in a Delta Airlines flight, but a law enforcement official briefed on the probe said the suspects account was plausible, and that he saw no reason to discount it.

An al Qaida operative in Yemen threatened the US saying we are carrying a bomb in a video posted online four days before Abdulmutallabs Christmas Day bid. The video did not contain any clear evidence of Fridays attempt, but it has attracted scrutiny because of reports that the plot may have originated in Yemen.

The Nigerian was today charged with trying to blow up a US plane mid-air and faces a prison term up to 20 years if convicted and a fine of up to $250,000.

Abdulmutallab was brought in a wheel chair to a conference room of a Detroit hospital, where he is admitted with burns, for a hearing. He wore a green hospital gown and blue socks and had one hand cuffed to his chair.

Abdulmutallab, 23, was charged with willfully attempting to destroy the Amsterdam-Detroit flight by placing a destructive device in the aircraft. The charge carries a prison term of 20 years, said Action News of Detroit whose reporter was one of the two journalists allowed inside the make-shift court room.

During the arraignment, Abdulmutallab did not say much. He did speak very good English. He answered the questions that Judge Paul Borman asked, telling him that he understood the charges he was facing, the paper said.

He spoke with a pleasant demeanour, and appeared more nervous than scared, a Detroit News report said.

The report said the suspect appeared 16-17 years old, much younger than his real age. Asked how he was doing, he said: Better than yesterday.

Abdulmutallab said he did not have the money to hire an attorney, though his father is a wealthy Nigerian banker.

Abdulmutallabs name was not unknown to US authorities. His father recently told the US embassy in Nigeria that he was concerned about his sons increasingly extremist religious views. After his fathers warning, federal authorities in Washington opened an investigative file and Abdulmutallabs name ended up in the American intelligence communitys central repository of information on known or suspected terrorists.

The suspects name was inserted last month into the Terrorist Identities Datamart Environment, or Tide. About 550,000 names are registered in the Tide. A subset of that is the Terrorist Screening Data Base (TSDB), which has about 400,000. Fewer than 4,000 names from the TSDB are on the no-fly list, and an additional 14,000 on a selectee list that calls for mandatory secondary screening, an US official said. At the time the name was recorded in the database, the official said, there was insufficient derogatory information available to put him in the TSDB, no-fly or selectee lists.